Curved Type Pneumatic Artificial Rubber Muscle Using Shape-Memory Polymer

A novel pneumatic artificial muscle actuator is presented which is based on the design of a conventional curved type pneumatic bellows actuator. By inhibiting the extension of one side with fiber reinforcement, bending motion can be induced when air is supplied to the internal bladder. In this study, we developed a new actuator by replacing the fiber reinforcement with a Shape-Memory Polymer (SMP). The SMP can be deformed above its glass transition temperature (T-g) and maintains a rigid shape after it is cooled below T-g. When next heated above T-g, it returns to its initial shape. When only part of our actuator is warmed above T-g, only that portion of the SMP is soft and can actuate. Therefore, the direction of the motion can be controlled by heating. Moreover, our actuator can be deformed by an external force above T-g and fixed by cooling it below T-g.